Piston for internal combustion engines

ABSTRACT

A piston for an internal combustion engine with a ring-shaped cooling space arranged in the piston top which is connected with a feed bore and with a discharge bore for the cooling medium; in particular, the piston has an eccentrically arranged combustion space recess about which the cooling space is laid as an openring whose ends are connected with the feed bore and the discharge bore, respectively.

United States Patent [1 1 Hoffmann 1 June 12, 1973 PISTON FOR INTERNALCOMBUSTION ENGINES [75] Inventor: Heinrich l-lotfmann,

Stuttgart-Geroksruhe, Germany [7 3] Assignee: Daimler-BenzAktiengesellschaft,

Stuttgart-unterturkheim, Germany 22 Filed: Nov. 26, 1971 211 Appl. No.:202,530

[30] Foreign Application Priority Data Nov. 27, 1970 Germany P 20 58410.5

[52] U.S. Cl. 123/4135, 92/186 [51] Int. Cl. F0lp 3/10 [58] Field ofSearch 123/4135, 41.16,

" 123/193 P, 32 A, 32 B, 32 C; 29/156.5 A; 92/176, 186

[5 6] References Cited UNITED STATES PATENTS 2,622,570 12/1952 Nallinger123/32 C 2,865,348 12/1958 Kramer et al 123/4135 FOREIGN PATENTS ORAPPLICATIONS 1,033,954 7/1958 Germany 92/176 854,804 11/1960 GreatBritain 123/32 A 1,244,830 9/1960 France 123/4135 1,141,494 12/1962Germany 123/4135 12/1962 Great Britain 29/1565 A Primary Examiner-AlLawrence Smith Attorney-Craig, Antonelli & Hill [57] ABSTRACT A pistonfor an internal combustion engine with a ringshaped cooling spacearranged in the piston top which is connected with a feed bore and witha discharge bore for the cooling medium; in particular, the piston hasan eccentrically arranged combustion space recess about which thecooling space is laid as an open-ring whose ends are connected with thefeed bore and the discharge bore, respectively.

2 Claims, 2 Drawing Figures 1 PISTON FOR INTERNAL COMBUSTION ENGINES Thepresent invention relates to a piston for internal combustion engineswith a ring-shaped cooling space arranged in the piston top, which isconnected with a feed bore and with a discharge bore for the coolingmedium, and more particularly the present invention relates to a pistonwith an eccentrically arranged piston combustion space recess aboutwhich the cooling space is placed.

In pistons of this type the cooling spaces are normally constructed asclosed rings, in which the connections for the cooling medium supply andthe cooling medium discharge are located mutually opposite along adiameter through the ring. If such an annularly shaped cooling space isarranged about a piston combustion space recess, generally a uniformheat removal in relation to the circumference of the combustion spacerecess takes place by the cooling medium. For centrally or coaxiallyarranged combustion space recesses a circumferentially uniform heatremoval by the cooling medium is therefore quite desired, however, thisis not the case for combustion space recesses which are arrangedeccentrically to the center longitudinal axis through the pistonsbecause in that case a cooling takes place also in those areas where itis not necessary as such. Those are the areas of the piston in which thecombustion space recess is located further away from the pistoncircumference than in other areas.

The present invention is concerned with the task to so construct acooling space in the piston that a cooling is effected deliberately onlywhere a cooling is absolutely necessary, and more particularly with acooling medium that is still as cold as possible.

The underlying problems are solved according to the present invention inthat the cooling space is constructed as open ring, to one end of whichis connected the supply bore and to the other end of which is connectedthe discharge bore.

An aimed-at, desired cooling of these piston areas which necessitate anadditional cooling is realized in a simple manner by the presentinvention. Piston areas from which heat is given off to the cylinder,without having to utilize additional means, remain outside the effectivearea of the cooling medium. As a result thereof the additional pistonareas to be cooled can be supplied with a relatively cold coolingmedium. An additional advantage results with the cooling of pistons ininternal combustion engines with cylinder rows of V- shape wherein onecylinder row endangered piston areas and in the other cylinder rownon-endangered piston areas are disposed at the pressure side of thepiston, i.e., with identical pistons the cooling requirements in bothcylinder rows are different in that simply the function of the feed anddischarge bores for the cooling medium are interchanged from cylinderrow to cylinder row. Furthermore, it is achieved by the presentinvention that the cooling medium flows faster on the inside of thecooling space according to the present invention than when a splittingup of the cooling medium stream takes plase as occurs in a closed ring.

Accordingly, it is an object of the present invention to provide apiston for internal combustion engines which avoids by simple means theaforementioned shortcomings and drawbacks encountered in the prior art.

Another object of the present invention resides in a piston for internalcombustion engines with a cooling means arranged therein that assurescooling only within those piston areas actually requiring suchadditional cooling.

A further object of the present invention resides in a piston forinternal combustion engines with an eccentrically arranged combustionspace recess which is provided with a cooling means effectively coolingonly those areas of the piston top which are endangered by the eccentriclocation of the combustion space recess.

A still further object of the present invention resides in a piston forinternal combustion engines which assures a more rapid flow of thecooling medium and therewith a more intense cooling due to the lowertemperature of the cooling medium.

There and further objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, one embodiment in accordance with thepresent invention, and wherein FIG. 1 is a plan view of a piston inaccordance with the present invention, and

FIG. 2 is a cross sectional view through the piston taken along line11-11 of FIG. 1.

Referring now to the drawing wherein like reference numerals are usedthroughout the two views to designate like parts, a combustion spacerecess 2 is arranged in a piston 1. This combustion space recess 2 isconstructed axially symmetrically. Its center longitudinal axis 3 islocated eccentrically to the center longitudinal axis 4 through thepiston 1. For purposes of cooling preferred piston areas about thecombustion space recess 2 a ring-shaped cooling space 5 is provided inthe piston top which is constructed as open ring. A feed bore 6 isconnected to one end of the open ring forming the cooling space 5 and adischarge bore 7 is connected to the other end thereof. The function ofthese two bores 6 and 7 can be interchanged if so desired or required.As can be seen from FIG. I, the cooling space 5 is disposed about theaxially symmetrically constructed combustion space recess 2 but does notextend over 360 of the circumference thereof but instead terminateswithin that area of the piston top which does not require any additionalcooling due to the presence of a larger amount of heat-conductingmaterial effecting removal of heat in the direction toward the cylinderwalls.

While I have shown and described only one embodiment in accordance withthe present'invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to those skilled in the art and I therefore do not wish to belimited to the details shown and described herein but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

What I claim is:

1. A piston for internal combustion engines with cooling space meansarranged in the piston head and connected to a supply bore and to adischarge bore for the cooling medium, characterized in that the coolingspace means is constructed as open-ring, to one end of which isconnected the supply bore and to the other end of which is connected thedischarge bore, said piston being provided with a combustion spacerecess arranged in the top thereof, the cooling space means beingarranged about only a portion of the combustion space recesscorresponding to those areas of the piston top endangered by heat, thecombustion space recess being arranged eccentrically with respect to thepiston axis and the cooling space means being arranged about thecombustion space recess at least within those areas thereof spacedcloser to the circumference of the piston, the piston combustion spacerecess being axially symmetrical and the cooling space means extendingabout the circumference thereof to an extent greater than 180 but lessthan 360 of the circumference of the recess, the open-ring coolant spacemeans being disposed between the side walls of the combustion spacerecess and the side walls of the piston, and the opening in theopen-ring coolant space means being located on that side of thecombustion space recess which is more remote from the side walls of thepiston.

2. A piston for internal combustion engines with cooling space meansarranged in the piston head and connected to a supply bore and to adischarge bore for the cooling medium, characterized in that the coolingspace means is constructed as open-ring, to one end of which isconnected the supply bore and to the other end of which is connected thedischarge bore, the piston being provided with a combustion space meansarranged eccentrically with respect to the piston axis and the coolingspace means being arranged about only a portion of the combustion spacerecess corresponding to those areas of the piston top endangered by theheat, said areas being spaced closer to the circumference of the piston,the open-ring coolant space means being disposed between the side wallsof the combustion space recess and the side walls of the piston, and theopening in the open-ring coolant space means being located on that sideof the combustion space recess which is more remote from the side wallsof the piston. II!

1. A piston for internal combustion engines with cooling space meansarranged in the piston head and connected to a supply bore and to adischarge bore for the cooling medium, characterized in that the coolingspace means is constructed as open-ring, to one end of which isconnected the supply bore and to the other end of which is connected thedischarge bore, said piston being provided with a combustion spacerecess arranged in the top thereof, the cooling space means beingarranged about only a portion of the combustion space recesscorresponding to those areas of the piston top endangered by heat, thecombustion space recess being arrangeD eccentrically with respect to thepiston axis and the cooling space means being arranged about thecombustion space recess at least within those areas thereof spacedcloser to the circumference of the piston, the piston combustion spacerecess being axially symmetrical and the cooling space means extendingabout the circumference thereof to an extent greater than 180* but lessthan 360* of the circumference of the recess, the openring coolant spacemeans being disposed between the side walls of the combustion spacerecess and the side walls of the piston, and the opening in theopen-ring coolant space means being located on that side of thecombustion space recess which is more remote from the side walls of thepiston.
 2. A piston for internal combustion engines with cooling spacemeans arranged in the piston head and connected to a supply bore and toa discharge bore for the cooling medium, characterized in that thecooling space means is constructed as open-ring, to one end of which isconnected the supply bore and to the other end of which is connected thedischarge bore, the piston being provided with a combustion space meansarranged eccentrically with respect to the piston axis and the coolingspace means being arranged about only a portion of the combustion spacerecess corresponding to those areas of the piston top endangered by theheat, said areas being spaced closer to the circumference of the piston,the open-ring coolant space means being disposed between the side wallsof the combustion space recess and the side walls of the piston, and theopening in the open-ring coolant space means being located on that sideof the combustion space recess which is more remote from the side wallsof the piston.